Coralie Hughes, Jim Masterson and Betsy Steiner

Credit: Photos by Deborah Kalas There are 18 thoracic vertebrae with ribs attached that form the trunk of the horse. As you can see, the withers are actually long spinous processes that project up between the scapulae from the fourth through the eighth thoracic vertebrae (T4 through T8) and can be as long as 10 inches. The blue structure that runs from the sacrum, along the back, and hooks into the lower cervical spine and onto the poll is the nuchal ligament.
Instruction

Dressage Movements Revealed

How a horse's physiology relates to dressage at every level